Electrothermal contact mechanism



July 6 1926.

. 2,591,022 G. A. DE LANGIE ET AL ELECTROTHERMAL CONTACT MECHANISM FiledApril 11, 1923 2 Sheets-Sheet l Lem fie. #0 1 Pefcr D Q9 Patented July6, 1926.

UNITED STATES PATENT OFFICE.

GODFREY A. DE LANGIE AND PETER DE LANGIE, F NEWPORT, RHODE ISLAND.

Application med A ru 11, 1923. Serial No. 831,458.

This invention relates to an electro-thermal control mechanism which isparticularly adapted for use in connection with electric irons,sterilizers, and other electrically ,heated devices and appliances.

In the use of devices and appliances of the character mentioned, whichare heated by means of an electric current, it is highly desirable toprovide means for automatically 1o breaking 'the electric currentthrough the resistance element when the temperature of the device orappliance has been raised to a redetermined point, and to effect thebreakmg of the current with certainty and at a substantially fixed pointon the temperature scale at all times.

The desiderata enumerated above are of great importance by reason of thewide use of electricity for thepurpose of heating appliancesof thischaracter, the fact that in many cases the operator is more or lessunfamiliar with the use of the electric current for the development ofheat and consequently liable to become careless or negligent in 2 theregulation and control of the same, as

well as the necessity in many cases for preventing any materialoverheating of the apparatus by reason of the danger of destroying theelectrical connections, causing injury to material, fires, etc. Theprincipal object of the resent invention is to provide an improveelectro-thermal control mechanism of s mple construction which is hi hlyeflicient in operation and as readily adapte for use in connection withelectrically heated devices and a pliances generally to insure a properan certain breaking of the electric current at -or sub stantially at apredetermined point on the temperature scale.

A further object of the invention is to provide an improved electriciron structure having eificient means for breaking the electric circuitthrough the heating element at substantially a fixed tem erature,together with means for closing t e electric circuit when broken,

Qther objects and advantages of the invention relate to various improveddetails of construction and improved arrangement of the arts as will bemore fully set forth in the. etailed description to follow.

Referring to the drawings: Fig. 1 is'a side elevational view of an atasatlttoa tachment for an electric iron or the like embodying one form ofthe invention.

Fig. 2 is an end elevation of the structure shown in Fig. 1.

Fi 3 is a sectional view, taken along the lme 33 of Fig. 2.

Fig. 4 is a sectional view, taken along the line 4-4 of Fig. 2.

Fig. 5 is a perspective view of the attachment as applied to an electriciron of the usual construction, certain portions being broken away tobetter illustrate the position of the operative parts.

Fig. 6 is a horizontal sectional view of a modified form ofthe/invention as applied to an electric iron, taken along the line 6-6of Fig 7, and,

ig. 7 is a vertical sectional view of the structure shown in Fig. 6.

In that form of the invention shown in Figs. 1 to 5 of the drawingswherein one form which the invention may assume in practice is shown asan attachment for an electric iron, 1 designates a housing made. up ofsections 2, 3 and 4, and adapted to be secured to a suitable part, asthe cover 26, of an electric iron of the usual construction. Thesections 2, 3 and 4 are secured together in any suitable or desiredmanner to hold the operative elements of the apparatus in properposition relative to each other and form a suitable housing for thesame. Secured in suitable recesses formed in the sections 2 and 3 andheld in position by the attachment of the sections 2' and 3 to eachother are terminals 5 and 6 of an electric circuit adapted to beconnected to a resistance element 7 by connections 8 and 9. Theterminals 5 and 6 may be properly insulated from the sections 2 and 3 byinsulated coverings 10 or the sections 2 and 3 may be formed ofinsulating material if desired. The electric connection 9 passesdirectly from the terminal 6 to its point of attachment to theresistance element while the terminal 5 terminates a slight distancefrom the end of the connection 8, the space there between being adaptedto be bridged by a movable contact 11.

The contact 11 is suitably secured to a movable switch 12, as bya screw13, and the switch member 12 is preferably pivoted pprtion of thehousing. The

switch 12 may e formed of insulating mateloo rial or the contact 11 maybe insulated therefrom in any desired manner. 'A block 16 is secured toone face of the switch member 12 by screws or other suitable fasteningdevices 17 the block 16 being provided at one end with inclined faces 18and 19 for a purpose which will be more fully described here inafter.

A spring 20 is positioned within the housing and bears against. one sideof the member 12 to force the same upwardly and thereby move 'thecontact 11 to open the circuit through the resistance element when theswitch member 12 is free to move in response to the action of thespring, and the member 12 has a, portion 21 projecting through one sideof the housing to serve as a handle by which the, member 12 may bemanually operated tomove the contact 11 to open or close the circuitthrough the resistance-element. A closed hollow elongated member 24 isprovided which has a portion 25 adapted to be inserted beneath the cover26 of the electric iron and extend along a part 27 of the iron and inproximity to the resistance element Twhereby the portion 25 of themember 24 may be influenced readily by the variations in temperatureexperienced by the iron when current is passed through the resistanceelement. The remaining portion of the member 24 is preferably flattenedand curved as indicated at 28 and lies in a groove 29 formed in thesection 3, the groove. or recess 29 being enlarged adjacent to the freeend of the portion 28 to permit the free end of the portion 28 of theheat responsive member 24 to move to different positions under theinfluence of variations in temperature.

'The member 24 is hollow substantially throughout its extent and theends thereof are closed to prevent the escape of air, gas or othersuitable expansible material which expands as the temperature is raisedand, in expanding, causes the bent'portion 28 of the member 24 to becomestraightened as in the well-known Bourdon tube. The free end of theportion 28 of the, heat responsive member is closed andis so positioned'as to engage the face 18 of the block 16 at ordinary temperatures, asshown in Fig. 2 of the drawings, whereby the movable switch 12 and thecontact 11 carried thereby are held in such position that the contact 11will close the circuit through the resistance element. As thetemperature of the iron increases the free end of the portion 28 movesto the left, as seen in Fig. 2, until when the maximum temperature whichit is desired to produce is reachedthe free end of the portion 28 movesout of engagement with the face 18 of the block 16 and permits theswitch '12 to be forced upwardly by the spring 20 to move the contact 11to open position thus breaking the circuit through the resistanceelement.

VVh-enever it is desired to close the circuit, by moving the contact 11into the position shown in Fig. 3, this may be done by manually pressingthe'handle 21 downward. If the temperatureof the iron at such timehappens to be above the temperature at which the switch is released theblock 16 will move past the free end of the'portion 28 of the member 24and the contact will be moved to closed position. In such case, however,the free end of the portion 28 of the member 24 will not engage the face18 of the block 16 to hold the switch closed and the spring 20 willcause the switch to open and break the circuit through the resistanceelement as soon as pressure upon the handle 12 is released.

If,- however, the temperature of-the iron has fallen to a point belowthat at which the automatic mechanism is set to operate for opening thecircuit before the handle 12 is manually actuated to close the circuit,the free end of the portion 28 of the member 24 will'have moved to theright as seen in Fig. 2 to such an extent as to "project beneath theedge of the block 16 so that the free end-of the portion 28 will engagethe inclined face 19 of the block. Further pressure downward upon thehandle 12 will then force the switch into the position shown in Fig. 2and close the circuit through the contact 11. In this case the free endof the por tion 28 will hold the circuit closed until the temperaturerises sufiiciently to again move the end of the heat; responsive memberout of contact with the block 16 and thus permit the spring 20 tomovethe contact and open the circuit.

While the switch may'thus' be actuated 'to automatically break thecircuit when a desired temperature is reached, the switch may also bemanually operated at any time to open the circuit by moving the handle21 upwardly. If this is done when the free end of the heat responsivemember occupies a position above the block 16, as shown in Fig. 2,. theinclined face 18 of the block will readil permit the block to force thefree end 0 the portion 28 of the heat responsive member to the left, asviewed in Fig. 2, and thus allow the block to move upwardly whereby thecircuit is broken.

An electric switch plug 30 of the ordinary type is shown in Fig. 5 aspositioned on the terminals 5 and 6 to connect the same with the usualcurrent sup 1y through the cord 31. Indicia such as if and 'On may beplaced upon the housing 1 toindicate to the operator the position of thehandle 21 when the circuit is open or closed.

From the above description it will be seen that a simple and efficientlyoperating form the structure, means is provided for automaticallybreaking the current throu h the resistance element of the iron at suctime as the temperature of the iron reaches a predetermined point topositively prevent over heating with consequent injury'to the iron orother materials.

Referring to that embodiment of the invention illustrated in Figs. 6,and 7 of the drawings, designates an electric iron provided witha baseplate 36, a top plate 37 and an electric heating element 38 interposedtherebetween. A layer of asbestos or other heat insulating material 39may be placed over the plate 37, and a cover 40 may be secured to theiron in an usual or desired manner as by screws 41.. erminas 42 and 43of an electric circuit are secured to the iron and suitably insulatedtherefrom, the terminal 43 being connected directly to the heatingelement 38 by a connection 44, while the terminal 42 is connected withthe heating element through a pivoted switch 45. The switch 45 is shownin the form of an elbow lever and is mounted to swing about a pivot post46. One of the arms 47 of the switch member is provided with springcontact members 48 which are adapted to engage the terminal 42 in oneposition of the switch and be separated therefrom when the switch ismoved to its open position to break the circuit through the heatingelement; A flexible connection 49 extends from the arm 47 of the switchto the heating element whereby a circuit is established through theheating element when the parts occupy the position shown in Fig. 6 ofthe drawings. A resilient member 50 connects the arm 47 with a portionof the iron to move the switch to open the circuit when the temperaturehas reached such a point that the movement of the switch to openposition is no longerobstructed by the heat responsive member.

A closed hollow heat responsive member 52 has a portion 53 embedded inthe base 36. adjacent to the heatingelement 38 and a curved portion 54extending above the asbestos layer 39. The heat responsive member may beof flattened tubular form with closed. ends, and may contain air orother material which is fluid at operating "temperatures and whichexpands with increase in temperature.

The free end 55 of the curved portion 54 of the heat responsive memberis adapted to occupy the position shown in'Fig. 6 at temperatures belowthat at which the circuit is to be opened. In this position of the partsthe end 55 contacts with the end of the arm 56 of the switch, as shown,to hold the switch against movement under the influence of the spring50. The screw 41 serves as a stop to prevent excessive movement of theswitch arm 56, and a coiled 52. In practice however contact may be madein various ways as b extending one of the spring contacts 48 intoposition to engage a contact in circuit with the heating element whenthe arts are in the position shown in Fig. 6. The arm 47 of the switchpasses through a slot 58 in the cover 40 and is provided with a manuallyoperable 'handle 59 bywhich the switch may be operated manually toeither open or close the circuit throu h the resistance element 38regardless o the position of the end 55 of the heat responsive member.The end 55 of the heat responsive member is rovided with inclined faces60 and 61 whlch permit the end of the arm 56 .to slide thereover ineither direction when the handle 59 is manually operated to eitheropenor close the circuit through the heating element at tempera turesbelow that at which the switch is automatically operated to open thecircuit to the heating element.

In the structure shown in Figs. 1 to 5 the terminals 8 and 9 may be'cutaway to permit-the usual contact posts of an electrically equipped ironto pass up into the hous ng a suflicient distance to contact with andmake an electric circuit with the terminals within the housing so as topermit the attachment to be applied to an electric iron without anymodification of the electric circuit within the iron. 1

While the heat responsive member has been described throughout thespecification as a closed hollow elongated member, since I the provisionof an elongated portion pro vides a ready means for positioning aconsiderable portion of the member in heat receiving position relativeto a heated part of the iron, it is to be understood that the heatresponsive member'may be. formed in a variety of shapes and its partsarran ed in difierentways provided the said mem r is constructed ofhollow form and closed to insure proper action on the part of theexpansible material therein contained.

While the electro-thermal control mechanism herein described has beenshown in connection with an electric iron structure in order toillustrate one form which the apparatus may assume in practice it is tobe understood that the same is not confined to use in connection withelectric irons but may be employed in connection with electricallyheated devices generally for automatically breaking the current toprevent overheating while at the same time permit-i ting the current tobe manually closed when the temperature of the heating element has beenlowered below the point at which the automatically operating mechanismis set to function. elements are so constructed and arranged as topermit the current through the heatin element to be made or broken bymanua actuation of the switch at temperatures below that at which themechanism is automatically actuated.

It is to be noted that the employment of a closed hollow elongated heatresponsive member of the character described as a control means forreleasing the switch and permitting the switch-to'be opened by theresilient means provided for the purpose when the temperature hasreached a predetermined point constitutes a simple and highly efi'icientautomatic mechanism for breaking the current through the resistanceelement which is capable of being arranged to operate with a high degreeof certainty and between extremely narrow limits of temperature. Thusthere is provided an apparatus of this character-which insures. acertain and positive operation of the parts, which is adapted to operateat substantially any desired-temperature, and

I which is capable of such uniformity of operation as to prevent injuryto the apparatus or materials by overheating.

What we claim is I 1. A. thermostatic control for electro-thermalmechanisms comprising a switch, and

a closed hollow heat responsive member havmg a curved end portion freeto move 1n anunobstructed path with variations in temperature forreleasing said switch at apredetermined temperature.

2. A thermostatic control for electro-thermal mechanisms comprising acircuit breaker for an electric circuit, a closed hollow elongatedmember-containing a heat expansible material and having a curved endportion movable into different positions in accordance with variationsin temperature, said member normally holding said circuit breaking meansin position to close the circuit but movable into position to releasesaid circuit breaking means when the temperature reaches a predeterminedpoint, and means circuit when released member.

for moving said circuit breaker to open the v by said elongated 3; Athermostatic control for electro-therma-l mechanisms comprising a springactuated member for breaking an electric circuit, and a closed hollowmember having a curved end portion normally holding said circuitbreaking means in position to close the cir- In addition to the abovethe holding said circuit breaking member in po- I sition to close saidcircuit but movable into position to release the spring actuated circuitbreaker and thereby open the circuit when the temperature has reached a'predetermined point.

5. A thermostatic control for electro-thermal mechanisms comprising acircuit breaker manually movable to either open or close an electriccircuit, spring means for moving said circuit-breaker into position toopen the circuit, and a closed hollow heat responsive member having acurved end portion movable to different positions in a directionradially of the curve responsive to variations in temperature fornormally holding the circuit breaker in position to close the circuitbut movable into position to release the circuit breaker whereby thecircuit breaker may be actuated by said spring means to open theelectric circuit when the temperature has reached a predeterminedpdiiit.

6. In an electro-tliermal control mechanism, a spring-actuated membermovable into position to open or close an electric circuit, and a closedhollow fluid containing heat responsive member having a bodily movableend portion provided with an inclined surface engaging saidspring-actuated member and adapted to hold said spring-actuated memberin circuit closing position at ordi nary temperatures but movable underthe influence of heat to release said spring actunism, manually operatedmeans for closing an electric circuit, means for breaking the saidcircuit when the temperature reaches a predetermined point, said lastnamed means including a. closed hollow elongated member havin a portionthereof bodily movable into ifierent positions responsive to temperaturechanges and adapted at normal temperatures to render said circuitbreaking means inoperative.

9. In an electro-thermal control mechanism a manually operated switchfor closing said circuit, resilient means for.moving said switch to openthe circuit, and a closed hollow elongated fluid containing memberhaving a portion bodily movable into different positions responsive tovariations in temperature adapted to hold said switch in closed positionat temperatures below a certain point and movable into position torender said resilient means operative to open the circuit when a certaintemperature has been reached.

10. In an electro-ther1nal control mechanism, a manually operated switchfor closing an electric circuit, resilient means for moving said switchto open the circuit, a closed hollow elongated fluid containing 'member,having a portion thereof bodily GODFREY A. DE LANGIE. PETER DE LANGIE.

